This invention is directed generally to the field of composite materials and more specifically to such materials which utilize intra-laminar structural and nonstructural connecting matrices.
A xe2x80x9ccomposite materialxe2x80x9d is generally defined as something formed of distinct parts with respect to the field of material science.
A wide variety of types of composites include the following example:
A layer of 0.125-inch polyester resin impregnated woven roving is catalyzed with approximately 1% - greater than 2% organic peroxide, to which has been previously layered 18-gauge cold rolled steel. A third layer is applied which consists of 0.125-inch fiberglass matting that has been pre-impregnated with polyester resin which is subsequently catalyzed with 1%- greater than 2% organic peroxide. A fourth (and final) layer of 18-gauge cold rolled steel is added.
Upon completion of this catalytic process, a multi-layer material is produced.
This exemplary composite provides a good illustration of a historical, yet current example in this field of endeavor. Completion of the above catalytic process provides a composite material that forms the basis of a raw material, or would in itself provide a raw material with which to construct, build, or otherwise be utilized as either a major or minor raw material in the construction of other materials or items.
Composites were originally conceived to provide a method for utilizing the optimum performance characteristics of each respective component in unison with each other in order to yield a new material which embodies the cumulative advantages of each respective component. Thus, a comprehensive understanding of the intended final application of the composite is essential during the design and engineering stage of the composite material itself, specifically, when choosing the appropriate components and bonding technologies that it is expected, should best meet the final design criteria.
This ability to engineer performance characteristics into the very base (xe2x80x9crawxe2x80x9d) materials that make up a product has resulted in an enormous variety of composite constructions. Today, one can find various constructions of composites in virtually every manufactured product. Raw materials that are used to construct components include, but are not limited to, ferrous and non-ferrous metals, plastics and polymers of all types, silicates, meta-silicates, resins, adhesives and glues, various fabrics, and many other materials. It is this ability to effectively combine various materials of practically all types that had led to the wide use of composites in virtually all areas of construction, from toys to jet fighters.
Currently, composites are constructed in such a manner that each layer of the composite is separate and distinct from other layers, as a combination of heterogeneous materials. These layers are joined to each other by various means, such as glues and adhesives, welds, catalytic action, as well as other methods. In virtually all cases, the composite construction consists of distinctively heterogeneous layers joined at their respective surfaces, resulting in a co-planar bond geometry.
Even in view of this advanced state of the art two factors have heretofore limited the performance and application of composites; specifically, these limiting factors are:
1. marginal bond integrity between heterogeneous layers; and
2. inability to enhance strength within homogeneous layers.
It is believed that marginal bond integrity is based, to a large degree, on limitations inherent to a co-planar bond geometry. More precisely, a co-planar bond geometry by definition yields a bond that exists in only two dimensions, namely the xe2x80x9cXxe2x80x9d dimension and the xe2x80x9cYxe2x80x9d dimension perpendicular to the xe2x80x9cXxe2x80x9d dimension coplaner with either composite layer 12, 14 of the composite article 10 shown in FIG. 1. Specifically, all bonding of adjacent homogenous and heterogeneous layers must occur within the limitations of their respective opposing symmetric surfaces. Thus, one can dimensionally model a co-planar bond geometry between two adjacent layers by the following Equation 1:
Abnd=(xdimYdim)xc3x972xe2x80x83xe2x80x83(Equation 1)
Where:
Abnd is Quantity of bond
xdim is Dimension xe2x80x9cxxe2x80x9d
ydim is Dimension xe2x80x9cyxe2x80x9d.
Additionally, Equation 2 provides an equation which models laminar bond(s) quantitatively for any composite construct consisting of more than two layers, as follows:
Abnd=Btot(xdimydim) is Quantity of bondxe2x80x83xe2x80x83(Equation 2)
where:
Ltot is Total composite layers
Btot=(Ltotxe2x88x921)xc3x972 is Total laminar bonds.
It is important to note that in both of the models represented in Equations 1 and 2 with reference to FIG. 1, no reference is made to the third dimension commonly referred to as xe2x80x9cZxe2x80x9d perpendicular to the X-Y plane. Specifically, bonding occurs as a direct consequence of the cumulative sum of the following three factors:
i. mechanical adherence or chemical (molecular) linkage of the bonding agent to the surface of the immediately adjacent layer 12; plus
ii. mechanical and chemical properties indigenous to the bonding material(s) or method(s); plus
iii. mechanical adherence or chemical (molecular) linkage of the bonding agent to the surface of the immediately adjacent layer 14.
Thus, bond integrity depends upon all three of these factors i-iii, above, to a large degree. Although it is known that many factors influence bond integrity, such as chemical contamination and subsequent degradation, poor surface preparation, and substandard manufacturing processes, bond integrity is further affected by one or more of these factors. Furthermore, the inventors of the present invention consider the thickness (hereinafter referred to as the xe2x80x9cZxe2x80x9d dimension) of the bond layer relatively trivial in a relativistic analysis of two-dimensional surface bonding according to the teachings of the related art. However, in a comprehensive analysis of a three-dimensional intra-laminar matrix/bond profile described later according to the present invention, the dimension xe2x80x9cZxe2x80x9d is of great importance.
Thus, the prior art has heretofore failed to recognize, let alone sufficiently address mechanical performance (generically referred to as xe2x80x9cstrengthxe2x80x9d) within homogeneous layers which is yet another limiting factor of prior art composite technology. Moreover, the prior art fails to address means for mechanically enhancing the physical properties of a homogenous layer of composite material without creating a distinct and, therefore, heterogeneous, additional layer, which would provide an important solution to a well-known problem in the material sciences art. An historical example of this is the three-layered composite consisting of:
Polyester resin impregnated fiberglass fabric laminated on each of its major surfaces to a thinner layer of ceramic (generic) material, of which all three layers are simultaneously catalyzed with 1% - greater than 2% organic peroxide.
In the above example, the polyester resin impregnated fiberglass is utilized solely as a means of reinforcing, and also providing additional strength to the overall composite. However, two additional heterogeneous layers, and their inherent disadvantages, have been created in the process. Specifically, adding the reinforcing layer creates the need to effectively bond two sets of two co-planar surfaces to each other, hence creating six additional opportunities for bond failure to occur in the resulting composite construction (See FIG. 5).
To summarize, prior art composite technologies suffer from a number of important disadvantages:
i. an absence of an industrially acceptable method for producing an intra-laminar structural matrix within a homogeneous composite layer;
ii. an absence of industrially acceptable mechanical methods of enhancing the mechanical performance characteristics of a homogeneous layer via modification of the homogeneous composite layer;
iii. current bonding technology, with the exception of some known welding techniques, is essentially two-dimensional, and thus limited in mechanical bonding effectiveness; and
iv. each additional reinforcing layer within a composite construct results in two sets of two co-planar surfaces that require bonding, thereby yielding six additional opportunities for potential inferior bond integrity. Poor bond integrity ultimately produces delamination of the native composite layers.
Accordingly, the present invention is directed to overcoming the above-identified deficiencies in the prior art, by, among other things:
(a) providing a method for mechanically creating an intra-laminar structural matrix within a homogeneous composite layer, subsequently making it possible for one;
(b) providing a method of enhancing the mechanical performance characteristics of a homogeneous layer via modification of the homogeneous composite layer;
(c) providing a method of creating a true three-dimensional bond, thus significantly advancing the state of the art bond technology with respect to composite materials; and
(d) providing a method of reducing or, in some cases, eliminating extraneous sets of co-planar surfaces that require bonding, thus significantly reducing opportunities for potential inferior bond integrity and subsequent delamination of the resulting composite construction.
Further objects and advantages of the present invention are to provide composite materials which exhibit improved performance characteristics, are easier and less expensive to manufacture, and are inherently more reliable by virtue of enhanced cohesiveness and overall structural integrity.
Yet additional objects and purposes of the present invention and apparatus manufactured by the method of the present invention will be apparent to persons familiar with this field of endeavor in view of the following description, drawing figures and claims.